Best way to notify costumers when restocking my Shopify shop for sold out items

There are a few ways to address this issue: First and foremost you need to update the product page, don't leave it as is. Hide the product, redirect, display it as out-of-stock or offer pre-order. To automatically hide out-of-stock products, use your Shopify store settings from your collections or use an additional inventory management app. To automatically hide out-of-stock products you need to: - Enable inventory tracking - Using the automated collection, set a condition that inventory stock has to be greater than 0. - If you want to hide it also from your collection you must do that in addition to the above actions. If you have a good product replacement or your page does not have much traffic, you might also consider redirecting customers to related products. It is easy to redirect the page to 301 or 302 redirects. For short term until restocking use 302 redirects. For indefinite or when one product is replaced by another use 301 redirect. This will allow the costumer to see other options available and would not harm your SEO too badly. You can read how to do this using the Shopify guide. Another option is to use an inventory management app that hides the out-of-stock automatically or replaces the out-of-stock button with a pre-order button. Shopify apps can assist you to show substitutes and sell products that are popular, out-of-stock and coming back in soon. Some inventory management apps include; Google Shopping Feed & Actions, Back in Stock and Stockify. These apps create a list of customers that signup for notifications and sends an email automatically as you restock.

For my shop I created a "signup for restock notification" button. This way I got a relevant list to send a blast to when I restocked.